Method and an apparatus for examining the seams of welded pipes

ABSTRACT

A method and an apparatus for the examination of the welding seams of welded pipes, wherein after forming the seam it is subjected to an ultrasonic examination along the entire length in production flow, certain locations of potential problems giving off distinguishing signals. Thereafter X-ray films are brought into engagement with the pipe wall at the locations resulting in such distinguishing signals, and finally an X-raying of the pipe wall is effected at these locations, said method and said apparatus being characterized by the steps or means of initially signalling to a positioning means all locations of a pipe giving off distinguishing signals during an ultrasonic pre-scan and then, at an X-ray station, placing X-ray films onto a backing at these signalled locations before the pipe is moved over said backing so that X-raying can be effected at these locations.

United States Patent Ries et al.

[ 1 Aug. 29, 1972 54] METHOD AND AN APPARATUS FOR EXAMINING THE SEAMS OFWELDED PIPES [72] Inventors: Karl Ries, l-lagdom 61; llehnut Wimmer,Jacobstrasse 39, Mulheim/Ruhr; Theodor Billet, Her-1.0gstrasse 35,Dusseldorf, all of Germany [22] Filed: Aug. 5, i970 21 Appl. No.: 61,387

301 Foreign Application Priority Data Aug. 6, 1969 19 39 933.8

[52] US. Cl ..73/67.5 R, 73I67.8, 250/52, 250/53 [51] Int. 29/04 [58]Field of Search ..73l67.5-67.9; 250/52, 53, 65 R [56] References CitedUNITED STATES PATENTS 2,437,688 3/ 1948 Forsell ..250/53 10/1965 Maklary....73/67.9 12/1969 Gewartowski ..73/67.8

[57] ABSTRACT A method and an apparatus for the examination of thewelding seams of welded pipes, wherein after forming the seam it issubjected to an ultrasonic examination along the entire length inproduction flow, certain locations of potential problems giving offdistinguishing signals. Thereafter X-ray films are brought intoengagement with the pipe wall at the locations resulting in suchsignals, and finally an X-raying of the pipe wall is effected at theselocations, said method and said apparatus being characterized by thesteps or means of initially signalling to a positioning means alllocations of a pipe giving 0E distinguishing signals during anultrasonic pre-scan and then, at an X-ray station, placing X-ray filmsonto a backing at these signalled locations before the pipe is movedover said backing so that X-raying can be effected at these locations.

5Claims,5DrairlngFigures PATENTEBmczs m2 SHEET 2 [IF 4 PATENTEDMZS I?!3.686.932

Slit! ll 4 PATENTED wees 1972 SHEET t [If 4 METHOD AND AN APPARATUS FOREXAMINING THE SEAMS F WELDED PIPES This invention relates to a method ofexamining the seam of welded pipes, wherein after the formation of thewelding seam it is subjected to an ultrasonic examination certainlocations of potential problems giving off distinguishing signals.Thereafter, at the locations resulting in such distinguishing ultrasonicsignals X-ray films are brought into engagement with the pipe wall andfinally at these locations an X-raying of the pipe wall is effected.This invention furthermore relates to an apparatus for performing thismethod.

The quality of welded large-size pipes decisively depends on the qualityof the welding seam. Therefore the clearance specifications require afull non-destructive examination of the welding seam at themanufacturing facilities where the large-size pipes are manufactured. Acomplete X-ray examination of the welding scam in the course ofproduction flow, however, is hardly capable of being conducted, becauseX-ray pictures generally require much time until they are evaluated andare too costly. Therefore the more sensitive and mechanized andtherefore quicker ultrasonic pulse examination of the entire weld seamas a preexarnination has been introduced, as is well-known in the art.The X- ray pictures are limited to those locations indicated aspotentially troublesome by giving off distinguishing signals in theultrasonic examination and to the end portions of the welding seam,because these are not totally scanned by the mechanized ultrasonicexamination. In this regard, the application of the films to the properlocations of the internal wall of the pipe resulted in greatdifficulties. When done manually it was cumbersome and therefore wastime consuming. A method is also known by means of which the films areconsecutively inserted at the locations to be X-rayed by means of anelongated arm containing a scale. This method is also verytime-consuming. In view of the ever increasing output of modernlarge-size pipe manufacturing plants, the time factor is almostunbearable.

An object of the invention is to provide a method of the type set forthinitially as well as an apparatus suited to perform such a method whichpermit a reduction of the time required for taking X-ray pictures sothat they can also be taken in the course of the production flow evenfor relatively high speed modern large-size pipe rolling mills.

According to this invention in a method of the above referred to typefirst of all the positions of all locations resulting in adistinguishing ultrasonic signal during a pre-seam of a pipe aretransmitted to a positioning means of the X-ray station and then theX-ray films are placed on a backing of the X-ray station at thesetransmitted locations before the pipe is moved over the backing so thatthe X-raying can be effected at these positions.

In the method according to this invention, the X-ray station can beprepared for X-raying before the pipe to be X-rayed is moved into theX-ray station, namely by bringing all films into their position aftersignalling the positions to the positioning means according to theindication of the positioning means. While then subsequently the pipe ismoved over these films and is X- rayed, the defect-prospective locationsof the next pipe can already be signalled to the positioning means. Themethod according to this invention thus permits short operating timesfor the X-ray pictures.

The apparatus provided for performing the method is characterized by thefact that it has a first station in which the pipe is inserted after theultrasonic examination or in which the pipe is examined by ultrasonicsand a second down-flow station including means movable in axialdirection of the pipe for X-raying, that both stations each have a striparranged coextensive of the pipe and at least as long as the pipe to beexamined and means which in both stations permit the same axialassociation of the pipe relative to the strip, that the two stripssimilarly are subdivided into a plurality of sections and each of thesections of the strip of the first station has a signal emitter and eachof the sections of the strip of the second station has a signalreceiver, the signal emitters and signal receivers of the respectivesections being connected to one another electrically, and that in thesecond station a support arm for receiving and urging the film againstthe internal wall of the pipe is provided which extends along the lengthof the pipe and is arranged adjacent the strip in a position axiallyfixed relative to the strip in such a way that it is positioned withinthe pipe after moving the pipe into the second station.

Preferably each section of the strip of the second station has at leasttwo signal receivers operable independently of one another.

According to a further object and feature of this invention, a rail isarranged in parallelism with the support arm on which at least one X-raydevice is capable of being moved by means of a control capable of beingprogrammed.

According to an advantageous embodiment of this invention, it iscontemplated that with the ultrasonic examination device there isprovided a spray gun and that an input device is arranged ahead of theX-ray device as viewed in direction of movement, including a strip whichin its length and its division into a plurality of sections correspondsto the strip of the X-ray device, each section being provided with aswitch from which a power line extends to the lamp of the correspondingsection of the strip.

Finally, it is proposed according to this invention to arrange two ormore X-ray apparatuses and possibly input devices in parallel behind awelding train.

With the foregoing objects in view, together with such additionalobjects and advantages as may subsequently appear, the invention residesin the parts, and in the construction, combination and arrangements ofparts disclosed, by way of example, in the following specification;reference being had to the accompanying drawings which form a part ofsaid specification and wherein:

FIG. 1 is a diagrammatic illustration of the movement of a pipe throughthe various stations,

FIG. 2 is a diagrammatic illustration of the first station including theinput device,

FIG. 3 is a diagrammatic illustration of the second station forX-raying,

FIG. 4 is a perspective illustration of including the input device, and

FIG. 5 is a perspective illustration of the second station for X-raying.

After welding, the pipes are expanded and thereby internally calibrated.After expanding, a water pressure testing step is performed. Thereafter,the pipes are tested in the end portion test stand 1 at their end porthefirst station tions along the entire pipe circumference by ultrasonicsfor laminations and inclusions. After end portion testing, the pipespass through the automatic ultrasonic test system 2. There all locationsalong the weld seams on the pipe 14 which emit a distinguishingultrasonic signal are automatically marked by means of a paint spraygun. Now X-ray pictures must be taken of the marked spots of the weldseam. For doing so, two X-ray devices 5 and 6 arranged in parallel areprovided, each of which is preceded by a first or preparation station 3and 4, respectively including an input device. A common darkroom 7including an automatic film developing machine is associated with thetwo X-ray devices 5 and 6. Furthermore, there is an evaluation room 8.After the X-ray test, the pipe leaves the X-ray device 5 or 6 and moveson to the release station 9 where the X- ray analysis is awaited. Thecapacity of this system is sufficient to prepare up to six X-raypictures per pipe in addition to the pictures at the weld seam endportions within the cycle of only a few minutes. A strip 11 is arrangedat the preparation station 3 and 4 in juxtaposed relationship to aroller bed 10. This strip has a length of about 41 feet corresponding tothe longest pipe to be examined. It is divided into 125 sections of cmseach. Each section is provided with a switch acting as a signal emitterand with a control lamp. The switches together form a bank 12, thecontrol lamps form a bank 13. In juxtaposed relationship to this strip11, the pipe 14 is stopped, the weld seam of which has been denominated15. It has a mark 16 generally midway which will come to a rest in theproximity of a particularly indicated section of the strip 11. in thisway, the axial association between the pipe 14 and the strip 11 isdetermined. This section has been marked by the arrow 17 in FIG. 2.Subsequently, those switches of the bank 12 are operated which arepositioned at the location of a paint mark on the pipe 14. Arrows 18,19, and show the operated switches in FIG. 2. When the switches areoperated, the control lamps of the strip 11 associated with the switchesare illuminated. The X-ray device 5 and 6 likewise has a strip 21serving as a positioning means. Regarding its length and its divisioninto 125 sections, it corresponds to the strip 11. The strip 21 isprovided with two banks 22, 23 of lamps as signal receivers. Eachsection of the strip 21 has two superimposed lamps. When the switches18, 19, 20 of the strip 11 are operated, the corresponding lamps 18,19', 20' of the lamp bank 22 of the strip 21 are illuminated. In thisway, the positions at which X-ray pictures are to be taken are signalledto the X-ray device 5, 6,7, 8 before the pipe 14 enters the X-ray device5, 6, 7, 8. The second lamp bank 23 of the strip 21 is provided for thepurpose of receiving the X-ray positions for the following large-sizepipe while the preceding pipe is still being tested.

In the X-ray device 5, 6, 7, 8, there is further provided a support arm24 secured to a support structure 25. An inflatable rubber hose 26 ispositioned on the support arm. As soon as the lamps 18, 19', 20 areilluminated, the operator can start to apply the X-ray films 28, 27, 29to the hose 26 at the signalled positions. As soon as this work is done,the pipe 14 is automatically moved into the X-ray room. In doing so, itmoves over the support arm 24 until the mark 16 is positioned oppositethe mark 17'. Subsequently, the free end portion of the support armextending out of the pipe is supported by an abutment 30. By depressinga pushbutton, the operator can now cause the hose 26 to inflate alongits entire length, with the films being disposed on this hose. In thisway, the films are pressed against the internal surface of the pipe. Thesizes of the films in longitudinal direction of the pipe are much largerthan the size of a section of the strip 21. A reliable image of a faultis thereby permitted even in case it is located at the border of asection.

A lead measuring tape 34 is placed in juxtaposed relationship to theweld seam on the pipe surface. It is provided for the purpose ofpermitting a non-confusible association between the X-ray picture andthe respectively tested location of a pipe.

By the operation of the switches 18, 19, 20 the program is memorized forsubsequent control of the automatic positioning of three X-ray devices31, 32, 33 which are movable in longitudinal direction of the pipe alonga rail (not illustrated). Concurrently with the operation of theinflatable rubber hose and the lowering mechanism for the measuringtape, the X-ray devices are moved into their X-raying positions. Now theexposing procedures are initiated from the control desk. If more thanthree X-ray pictures must be taken at one pipe, the X-ray tubesautomatically move into their new X-raying positions after terminationof the first exposing procedure.

Thereafter, the hose is automatically decompressed, and the lead measureis lifted up. The exposed films lie free and are lifted off the rubberhose 26 by the operator and are immediately conveyed to the darkroomthrough a conveyor belt. There the films are developed by means of anautomatic developing machine. The films are passed on to the evaluationroom 8 after being developed, where the critical weld seams are judgedon the basis of the X-ray films. The analysis result is transmitted tothe release station 9 where the X-rayed pipes are waiting. As a resultof the reports, the pipes are either released or passed on to anappropriate after treatment.

The system described is merely an embodiment of the invention by way ofexample. it can be modified in various ways without departing from thespirit of the invention. For instance, automation can be enhanced evenmore by automatically also transmitting the locations which result in asignal in the ultrasonic test. This could be done for instance in such away that the mark indication of the positions is effected on a recordingcarrier moved synchronously with the pipe, instead of on the pipe, forinstance on a magnetic tape recorder or a slide register. The signalscan automatically be scanned from the recorder and used for theoperation of the lamps on the strip 21 as well as for the provisionalcontrolling of the X-ray devices 31, 32, 33.

Thus, notwithstanding the illustrated use of the invention and themanner by which such use may be achieved, it is appreciated that changesand modifications will suggest themselves to others skilled in the artboth for uses similar to those illustrated as well as for other uses.The invention, therefore, is not to be deemed to be limited to the exactmode of execution above disclosed by way of example, and it will beunderstood that the invention embraces all such changes andmodifications in the parts, and in the construction,

combination and arrangement of parts as shall come within the purview ofthe appended claims.

What is claimed is:

l. A method of examining the seams of welded pipes comprising the stepsof subjecting said seam to an ultrasonic examination along its entirelength in such manner that locations of potential problems give off adistinguishing signal, noting such locations, signalling such locationsto an X-ray station before said pipes reach said station, positioningX-ray films at said station at spaced positions corresponding to thelocations, advancing said pipes to said station so that its locationsare in registry with the spaced positions where X-ray films have beenprovided, and X-raying said pipes at said locations.

2. A method according to claim 1, wherein said films are positioned on abacking, said pipes moving over said backing so that said X-rays arebeamed from outside said pipes toward films inside said pipes.

3. An apparatus for examining the seams of welded pipes comprising afirst station for receiving an ultrasonically pre-examined pipe whoselocations of potential problems have been noted, a second stationpositioned downstream of said first station and provided with meansmovable in axial direction for the pipe for X-raying, each stationhaving a strip arranged coextensive of the pipe and at least as long asthe pipe to be examined, said pipe being marked whereby it may bepositioned in both stations with the same axial association of the piperelative to the strips, the two strips being subdivided into a pluralityof sections and each of the sections of the strip of the first stationhaving a signal emitter respectively connected to a signal receiver oneach of the sections of the strip of the second station, the emittersbeing actuated in accordance with corresponding locations of said notedpotential problems upon positioning the pipe at the first station, asupport arm in the second station for receiving X-ray films positionedin accordance with locations indicated by the signal receivers, saidsupport arm extending along the length of the pipe and being arrangedadjacent the strip in a position axially fixed relative to the strip insuch a way that it is positioned within the pipe after moving the pipeinto the second station, and means for urging said support arm againstthe internal wall of a pipe in said second station.

4. An apparatus as defined in claim 3, wherein each section of the stripof the second station has at least two signal receivers operableindependently of one another, one of said receivers being used toreceive signals pursuant to which film is positioned for a pipeimmediately to arrive in said second station, the other of saidreceivers being used to receive signals from the next pipe in said firststation in preparation for the next positioning of the films.

5. An apparatus as defined in claim 3, including a rail parallel to saidsupport arm and carrying at least one X- ray device movable inaccordance with actuation of the emitters.

# i I. 1 l

1. A method of examining the seams of welded pipes comprising the stepsof subjecting said seam to an ultrasonic examination along its entirelength in such manner that locations of potential problems give off adistinguishing signal, noting such locations, signalling such locationsto an X-ray station before said pipes reach said station, positioningX-ray films at said station at spaced positions corresponding to thelocations, advancing said pipes to said station so that its locationsare in regIstry with the spaced positions where X-ray films have beenprovided, and X-raying said pipes at said locations.
 2. A methodaccording to claim 1, wherein said films are positioned on a backing,said pipes moving over said backing so that said X-rays are beamed fromoutside said pipes toward films inside said pipes.
 3. An apparatus forexamining the seams of welded pipes, comprising a first station forreceiving an ultrasonically pre-examined pipe whose locations ofpotential problems have been noted, a second station positioneddownstream of said first station and provided with means movable inaxial direction for the pipe for X-raying, each station having a striparranged coextensive of the pipe and at least as long as the pipe to beexamined, said pipe being marked whereby it may be positioned in bothstations with the same axial association of the pipe relative to thestrips, the two strips being subdivided into a plurality of sections andeach of the sections of the strip of the first station having a signalemitter respectively connected to a signal receiver on each of thesections of the strip of the second station, the emitters being actuatedin accordance with corresponding locations of said noted potentialproblems upon positioning the pipe at the first station, a support armin the second station for receiving X-ray films positioned in accordancewith locations indicated by the signal receivers, said support armextending along the length of the pipe and being arranged adjacent thestrip in a position axially fixed relative to the strip in such a waythat it is positioned within the pipe after moving the pipe into thesecond station, and means for urging said support arm against theinternal wall of a pipe in said second station.
 4. An apparatus asdefined in claim 3, wherein each section of the strip of the secondstation has at least two signal receivers operable independently of oneanother, one of said receivers being used to receive signals pursuant towhich film is positioned for a pipe immediately to arrive in said secondstation, the other of said receivers being used to receive signals fromthe next pipe in said first station in preparation for the nextpositioning of the films.
 5. An apparatus as defined in claim 3,including a rail parallel to said support arm and carrying at least oneX-ray device movable in accordance with actuation of the emitters.